This invention relates to a novel heat resistant and fire-proof synthetic material. More specifically, this invention relates to a heat resistant and fire-proof synthetic resin composition which comprises a thermosetting synthetic resin and a ceramic layer forming component.
There are numerous known processes for producing foamed materials by adding a foaming agent to a suitable synthetic resin. Furthermore, various kinds of foaming agents for use in such processes are known.
Such artificial foam materials may be classified into those of the organic type which comprises organic high molecular weight compounds as the base, and the inorganic type. Examples of organic high molecular weight compounds include polyethylene, polystyrene and polyurethane. As to inorganic foam materials, examples include concrete and glass foams. It is noted that concrete foam has independent cells and comprises a double salt of a cement polymer and a silicon dioxide and aluminum hydroxide as a film former. This type of polymer possesses a characteristic different from that of the plastic foam. Glass foam is a refractory material produced by adding a small amount of powdered carbon black as a foaming agent to a mass of powdered glass, uniformly mixing the components, heating the mass in a mold for foaming, cooling slowly, and then withdrawing the product from the mold. In this case, antimony trioxide, potassium sulfate, or boric acid may be added in order to balance the sintering speed of the glass and the rate of foaming by smoothly carrying out the decomposition of the foaming agent. However, this process is applied only to the production of foamed materials consisting mainly of glass.
Processes for producing synthetic resin foams in which organic high molecular and light weight compounds having a particular molecular construction of straight or branched chains are reacted gradually with a polyisocyanate or boric acid are well known. However, these processes suffer from the disadvantage in that special equipment as well as specific techniques for pouring and foaming are required. Furthermore, these processes are usually difficult to control.
The use of synthetic resin foams as construction materials is widespread. For obvious reasons, it is desirable to impart excellent anti-flame properties at high temperatures in the foamed materials. However, synthetic resins generally have poor heat resistivity and weather durability, as compared with wood, metal and ceramics. Despite these disadvantages, various synthetic resin materials have been widely used due to the good plasticity thereof and many attempts have been made to further improve their physical properties.
With respect to anti-flame properties, synthetic resins are generally classified into two categories: difficultly inflammable type and incombustible type. A difficultly inflammable resin will continue to burn during contact with a flame so that it cannot be said to be the perfect fire-proof material. As to the incombustible type, such material will not burn by itself. Furthermore, incombustible materials can be classified into a self-extinguishing type which produces on the surface thereof an incombustible and heat resistant layer when contacted with an atmosphere of high temperature, and an incombustible type which is stable to heat due to a structure like an inorganic material although it comprises an organic substance as the main component.